This invention relates to a method for routing calls to telephony devices when the telephone numbers used to identify the telephony devices have been converted from an old series of telephone numbers having a first numbering scheme to a new series of telephone numbers having a second numbering scheme.
When telecommunication networks for calls between subscribers via telephone, fax, computers or other methods are enlarged or changed there is often a need to carry out changes to the numbering schemes which are used to direct the calls. Normally number changes are carried out gradually, so that both the new and the old number for a subscriber are valid during a transitional period, for example for up to a year. After this for a further period of time a subscriber calling the old number is informed that a number change has occurred, and finally after a certain period of time the old number is removed.
The technology used today is that during the transitional period both the old and the new number are recorded in the network for each subscriber, and so while number changes are taking place double capacity is required for the storage of numbers. Where the subscriber has a portable number, that is when the subscriber has the ability to retain his number when he moves house or changes telecommunications operator, particularly great demands are made on capacity for storage of subscriber numbers in connection with numbering scheme changes. In addition information associated with the old number must be updated in two different places during the numbering scheme change, the first time when the call to the old number is to be directed to information that the number change has occurred, and the second time when the old number is to be removed. This is expensive in terms both of time and money, particularly when the change concerns very large numbering schemes.
The aim of the invention is to make it simpler and cheaper to carry out numbering scheme changes. An additional aim is also to make easier numbering scheme changes for portable numbers.
The aim of the invention is achieved by determining by means of an analysis whether the number belongs to the old or the new numbering scheme and if the analysis shows that the number belongs to the old numbering scheme it is converted by means of a conversion algorithm in a first database to a number according to the new numbering scheme, after which directing is carried out on the basis of the number according to the new numbering scheme. By this means only the number according to the new numbering scheme needs to be defined in the network. An important simplification is achieved if numbers which are found by the identification to belong to the new numbering scheme or which have been converted to the new numbering scheme are allocated directing information from a second database comprising only the new numbering scheme and thereafter are directed onwards on the basis of this directing information. As a result the need for number storage is reduced considerably, as the second database can comprise only numbers according to the new numbering scheme. A particular simplification is obtained if directing information from the second database is only allocated to portable numbers according to the new numbering scheme.
A further simplification is achieved by using a separate conversion algorithm in the first database for each number group in the old numbering scheme.
In the proposed device according to the invention the computer unit is arranged to determine whether the number belongs to the old or the new numbering scheme and is provided with a first database which is arranged to convert a number according to the old numbering scheme to a number according to the new numbering scheme by means of a conversion algorithm so that the network only needs to direct calls on the basis of numbers according to the new numbering scheme. The first database is suitably arranged to transfer the new number to a second database which is arranged to allocate directing information only to numbers according to the new numbering scheme. The second database can advantageously contain only portable numbers according to the new numbering scheme. In particular there is a separate conversion algorithm in the first database for each number group. This means that the second database can be made considerably smaller than previously, with a resultant simplification and saving.
Further advantages and characteristics of the invention are described in the patent claims and description.